Human respiratory tissues are a prime target for airborne environmental pollutants and carcinogens. The mucous cells that constitute almost 57% of the tracheobronchial epithelium are reportedly involved in such serious diseases as bronchitis, cystic fibrosis, inflammation, and cancer. The major objective of our research will be to establish primary and serial passaging cultures of mucus-secreting cells from the human tracheobronchial epithelium. These cells will facilitate a variety of important studies such as the regulation of synthesis and release of mucoproteins, identification and isolation of specific cell products for development of immunological agents, effects of hormones, growth factors, substrates and cell-cell interaction. In addition, it will become possible to study mechanisms of carcinogenesis involving fully differentiated mucous cells. Two major approaches will be used: first, by isolating homogeneous populations of mucous cells using cell separation techniques and passaging the cells in a suitable medium and a substrate; second, by developing continuously passaging cultures of tracheal cells and inducing the cells to undergo mucous cell differentiation. The culture medium modification will be made with respect to the essential and non-essential amino acids, hormones, growth factors, vitamins and colinergic factors. The primary and serial passaging cultures will be characterized on the basis of ultrastructural, histochemical, immunocytochemical and biochemical methods. The synthesis and secretion of muco-glycoproteins will be demonstrated by the incorporation of radioactive glycoprotein precursors such as 35SO4, and 3H-glucosamine. Subsequent to the propagations of mucous cell cultures in serum containing medium, we will also develop chemically defined serum-free medium for the cell cultures.